<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>静态定位</title>
    <style>
        div {
            border: 1px  solid black;
        }
        #div1 {
            width: 400px;
            height: 400px;
            margin: 10px auto;
        }
        #div2 {
            margin: 10px auto;
        }
        #div3 span {
            margin: 10px 20px;
            line-height: 80px;
        }
        
    </style>
</head>
<body>
    <div id="div1">block设定了尺寸</div>
    <div id="div2"> block没有设定尺寸</div>
    <div id="div3">
        <span>行内元素</span>
        <span>行内元素</span>
    </div>
</body>
</html>